Items of merchandise are often displayed for a potential purchaser to examine, and in some instances, operate the merchandise. For example, retail stores typically provide items of merchandise, particularly relatively expensive handheld electronics, on a display that allows a potential purchaser to examine and operate the merchandise, and thereby learn more about its features, in a powered state. To deter theft of the item of merchandise, retailers typically attach the item of merchandise to a merchandise display security device. The security device, including for example, mechanical tethers, sensors coupled to the merchandise by electrical or optical cables, and wireless monitoring systems, activate an alarm if the item of merchandise is detached from the security device by an unauthorized person, such as a potential shoplifter attempting to remove the merchandise from the display.
Merchandise display security devices are available in a variety of designs to meet both the display and security requirements of different types of merchandise. Conventional security devices include, but are not limited to, modular components that communicate via switching systems, tethered units that communicate with broader security systems, and stand-alone alarm modules having a base and associated sensors that attach to handheld electronics, such as cellular telephones, cameras, video equipment, and the like. Exemplary merchandise display security devices that are commercially available from the assignee of the present invention are shown and described in U.S. Pat. No. 7,740,214, U.S. Pat. No. 7,737,843, U.S. Pat. No. 7,710,266, U.S. Pat. No. 7,629,895, and U.S. Pat. No. 7,446,659, as well as U.S. Patent Application Publication No. 2009/0173868, the entire disclosures of which are incorporated herein by reference.
One of the most important developments in merchandise display security devices has been the provision of power from the security device to the item of merchandise. In this regard, the security device not only protects the item of merchandise from theft, but also allows a potential purchaser to examine and operate the merchandise in a powered state. The potential purchaser is more likely to purchase the item after having had an opportunity to evaluate the various features and capabilities of the merchandise. The security device in this instance serves not only as an alarming system to deter theft, but also as a conduit for providing power to the item of merchandise.
However, a problem arises with a merchandise display security device that provides power to an item of merchandise because the security device and the item of merchandise offered for sale generally have different power, and in particular, voltage requirements. In particular, the electronics of the security device must be provided with power at the proper operating voltage, while at the same time the security device provides power to the item of merchandise at an appropriate operating voltage for the merchandise. Different types of items of merchandise (e.g., cell phones, cameras, MP3 players, video recorders/players, etc.) from various manufacturers, as well as different models of the same type of merchandise from the same manufacturer, utilize customized power circuits that require particular operating currents and operating voltages. In designing a merchandise display security device to provide power to an item of merchandise via an electronic circuit within the security device, many variations are needed because each type, and potentially each model, of the merchandise may have unique power requirements, and in particular, a different operating voltage. Obviously, it is not cost efficient or practical for retailers to purchase, stock and install multiple merchandise display security devices that provide different operating voltages to the different types and models of merchandise to be displayed so that a potential purchaser may examine and operate the merchandise in a powered state.
Instead of providing a different security device for each type and model of an item of merchandise having a different operating voltage, manufacturers have developed security devices that deliver an appropriate operating voltage to more than one type or model of merchandise. For example, a merchandise display security device disclosed in U.S. Pat. No. 7,015,596 issued to Pail provides power to different items of merchandise via a single power cable, also referred to as an “adapter cable” or “power cord”, extending between an alarm sensor and the merchandise. The power cable includes a reference resistor and a calibrating voltage of the security device induces a voltage across the reference resistor that is measureable by electronics within the security device. The measured voltage across the reference resistor is one way of identifying the operating voltage associated with the item of merchandise so that the security device can provide an appropriate operating voltage to power the merchandise.
U.S. Pat. No. 6,756,900 issued to Leyden discloses a merchandise display security device including an alarm sensor for the item of merchandise with a movable voltage selector switch having a plurality of positions that allow store personnel to select an appropriate operating voltage to be delivered to the item of merchandise via a suitable power cable. The alarm sensor is configured to provide any one of a plurality of discrete operating voltages to the item of merchandise determined by the position of the voltage selector switch.
U.S. Pat. No. 6,509,659 issued to Carroll discloses yet another merchandise display and security system for delivering an appropriate operating voltage to an item of merchandise displayed on a security device. The system described in the Carroll patent utilizes a power cable having a universal connector end for attaching to an alarm sensor of the security device, and a customized connector end tailored to the power requirements of the item of merchandise being displayed. A pin layout at the customized end determines which pins of the universal connector end are utilized to complete an electrical circuit through the power cable. The completed circuit identifies the appropriate operating voltage that the security device should provide via the power cable to power the item of merchandise on display.
U.S. Pat. No. 5,535,274 issued to Braitberg discloses yet another variation of a power cable extending between a merchandise display security device and an item of merchandise. The power cable described by Braitberg may be configured by a number of pins reserved at the processor (i.e., “common”) end of the power cable. The interface at the merchandise end of the power cable provides a communications link that establishes a binary pattern of identification data unique to the item of merchandise to be powered. The security device uses the binary pattern to identify the type and model of merchandise connected to the power cable, and thereby determine the appropriate operating voltage for the merchandise from an associated look-up table.
Accordingly, merchandise display security devices are known that include electronics for identifying an item of merchandise attached to the security device and for delivering an appropriate operating voltage to the merchandise. The known security devices, however, fail to account for system error and component tolerances that could misidentify the merchandise. Such an occurrence could, of course, lead to the security device providing an inappropriate operating voltage to the merchandise, thereby causing serious damage to the merchandise and possibly to the security device. Without limiting the invention in any manner, one object of the invention is to provide a voltage regulator and associated method for determining an appropriate operating voltage for an item of merchandise displayed on a security device and for providing power to the merchandise in a manner that accounts for system error and the tolerances of individual components of the system so that a potential purchaser may examine and operate the merchandise in a powered state.